Laravel Migration MySQL 1215：無法添加外鍵約束

Question

我有一個我無法添加的外鍵問題。

Schema::create('relation', function (Blueprint $table) {
    $table->engine = 'InnoDB';
    $table->string('applicantpseudo');
    $table->string('wishpseudo');
    $table->timestamps();
    $table->boolean('incall')->default('0');

    $table->primary(['applicantpseudo', 'wishpseudo']);
});

Schema::create('match_applicant', function (Blueprint $table) {
    $table->engine = 'InnoDB';
    $table->string('pseudo');
    $table->string('applicantpseudo');
    $table->string('wishpseudo');
    $table->boolean('match')->default('0');

    $table->primary(['pseudo', 'applicantpseudo', 'wishpseudo']);
//        $table->foreign('pseudo')->references('pseudo')->on('users');
//        $table->foreign('applicantpseudo')->references('applicantpseudo')->on('relation');
        $table->foreign('wishpseudo')->references('wishpseudo')->on('relation');
});

這兩條注釋線都有效。

但是wishpseudo返回了1215 Mysql錯誤。

謝謝

您可以在此處找到SQL腳本

--
-- Structure de la table `relation`
--

DROP TABLE IF EXISTS `relation`;
    CREATE TABLE IF NOT EXISTS `relation` (
  `applicantpseudo` varchar(191) COLLATE utf8_unicode_ci NOT NULL,
  `wishpseudo` varchar(191) COLLATE utf8_unicode_ci NOT NULL,
  `created_at` timestamp NULL DEFAULT NULL,
  `updated_at` timestamp NULL DEFAULT NULL,
  `incall` tinyint(1) NOT NULL DEFAULT '0',
  CONSTRAINT pk_relation PRIMARY KEY (`applicantpseudo`,`wishpseudo`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

--
-- Structure de la table `match_applicant`
--

DROP TABLE IF EXISTS `match_applicant`;
CREATE TABLE IF NOT EXISTS `match_applicant` (
  `pseudo` varchar(191) COLLATE utf8_unicode_ci NOT NULL,
  `applicantpseudo` varchar(191) COLLATE utf8_unicode_ci NOT NULL,
  `wishpseudo` varchar(191) COLLATE utf8_unicode_ci NOT NULL,
  `match` tinyint(1) NOT NULL DEFAULT '0',
  CONSTRAINT pk_relation PRIMARY KEY (`pseudo`,`applicantpseudo`,`wishpseudo`),
  CONSTRAINT test FOREIGN KEY (wishpseudo) REFERENCES relation (wishpseudo)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

我在http://sqlfiddle.com/上有錯誤，但我沒有找到錯誤，我需要幫助......

Answer 1

我不明白你想要實現的目標。 但試着打電話

$table->foreign('wishpseudo')->references('wishpseudo')->on('relation'); 這在新的Schema::create()是這樣的：

 Schema::create('relation', function (Blueprint $table) {
        $table->engine = 'InnoDB';
        $table->string('applicantpseudo');
        $table->unsignedInteger('wishpseudo');
        $table->timestamps();
        $table->boolean('incall')->default('0');

        $table->primary(['applicantpseudo', 'wishpseudo']);
    });

    Schema::create('match_applicant', function (Blueprint $table) {
        $table->engine = 'InnoDB';
        $table->string('pseudo');
        $table->string('applicantpseudo');
        $table->string('wishpseudo');
        $table->boolean('match')->default('0');

        $table->primary(['pseudo', 'applicantpseudo', 'wishpseudo']);
    //        $table->foreign('pseudo')->references('pseudo')->on('users');
    //        $table->foreign('applicantpseudo')->references('applicantpseudo')->on('relation');

    });

    Schema::create('match_applicant', function (Blueprint $table) {

            $table->foreign('wishpseudo')->references('wishpseudo')->on('relation');
    });

Answer 2

你可以嘗試下面的代碼：

$table->integer('wishpseudo')->unsigned();
$table->foreign('wishpseudo')->references('id')->on('relation');

Answer 3

我希望這對你有用

Schema::create('match_applicant', function (Blueprint $table) {
    $table->string('wishpseudo')->references('wishpseudo')->on('relation');
});